The fashion stylists who rock!

They are the caretakers of cool — but they rock their work frombehind the scenes.

Now, stylists finally are getting their chance to step into the spotlight. While performers would like fans to think they came onto the scene looking fabulous, their signature looks or locks are often the work of a stylist. That’s as true for Nicki Minaj’s Barbie look as it is for Judas Priest’s studded jackets, Biggie Small’s flamboyant colors and luxurious fabrics, and even the Beatles’ haircuts.

The behind-the-scenes tastemakers are the focus of a new YouTube documentary series about stylists, “Rockin the Seams.”

Tara O’Connell, a stylist at Fuse TV, came up with the series showcasing these unsung heroes of style. She tracks down everyone from Leslie Cavendish, the Beatles’ hairdresser, to Madonna’s early stylist Maripol, to Christian Joy, who created costumes for singer Karen O of the Yeah Yeah Yeahs.

Eamonn McCormack/WireImage

Nicki Minaj became a huge star after getting all dolled up.

“It’s only recently that stylists are widely recognized,” O’Connell says. “Now people understand what a stylist is, because of the Rachel Zoe show and blogs, but I don’t think people understand the real extent of their work and their influence on certain looks and in pop culture.”

Cavendish, for instance, “was thrilled to be interviewed because he’d been interviewed only twice, on the BBC, but not a full interview,” she says.

Rocker stylist Ray Brown exclaims, “Just like the rock stars!” when O’Connell miked him up for his interview. When she expressed surprised he’d never been interviewed, he told her with self-deprecation, “In the ’80s, I was just the guy making the clothes.”

Christian Joy helps outfit Karen O.

He and the other stylists included in the Web series, did a lot more than that — and many have had lasting influence.

Here’s one secret of heavy metal: Judas Priest has “basically never” worn real leather onstage. It’s all Brown’s proprietary washable faux leather, which was made exclusively for him and his clients.

“No one else has it. No one else can get it,” he told O’Connell for the series. “You can machine-wash and dry it, and it’s stronger than real leather.”

Brown also can take credit for popularizing pyramid studs, which started as “basically a Judas Priest thing” on belts, guitar straps and jackets.

Tara O’Connell put together the YouTube series ‘Rockin the Seams’

Still, Brown admonishes, you can’t just throw studs on a shirt and call it a day.

“You don’t add something onto clothing just for the sake of adding it onto clothing,” he says. “The heavily studded stuff accents it …. It’s there to enhance it.”

Lady Starlight met Lady Gaga when she came into lower East Side bar St. Jerome, where Starlight was go-go dancing, and soon befriended her.

Amy Sussman/Getty Images

Ladies Gaga (l.) and Starlight have bonded over fashion.

Starlight says she didn’t influence Gaga’s style literally. “Her fashion and her look is entirely her own creation,” she says.

However, what the stylist says she did influence was the attitude and the way Gaga approached wearing out-there designs.

“What I think was important that I gave to her as a friend was just the confidence to say, ‘F— it!’ Just to go all the way. The more offensive, the more reaction you get from somebody, the better. That’s the sign that’s the right look,” she told O’Connell.

Cavendish, the Beatles’ hairdresser from late- 1966 to ’75, was working in a salon on Bond St. when Jane Asher, Paul McCartney’s girlfriend, came in one day and asked if he would cut her boyfriend’s hair.

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The Beatles’ fab haircuts were the rage in the ’60s

“I knew her boyfriend was Paul McCartney,” he says. “I didn’t know if it was real or not, but I was a Beatles fan.”

Excited, he took his scissors to Paul’s house for a trim. He soon met the other Beatles and began cutting their hair as well. (Ringo’s wife was a hairdresser, so she often cut his hair.)

“The secret was to cut it so it didn’t look like you were having a haircut,” he says. “People ask me, ‘Did they use any products?’ The only thing you’d put on would be some conditioner.”

He didn’t always cut their hair. Sometimes he simply washed and styled it.

Cavendish adds that Paul “wasn’t a prima donna, like, ‘I must have my hair washed and I can’t do it myself.’ ”Nicki Minaj, known for her over-the-top, cartoonish Barbie look, hit it big when stylist Fatima B. — who was working for teen magazine Right On as fashion director at the time — pitched the then-new artist to her editor with the idea, “We should shoot [her] as a Barbie!” The photos made the cover.

All Minaj needed was some fairy dust to become the complete package, says Fatima B.

“I feel like she was already going to get to this point some way, somehow, but I feel like her image … just needed a bit of the vision,” she says. “We just needed to see it to believe it.”

Fatima B. is the guru behind many of Nicki Minaj’s styles.

You don’t necessarily need a degree in fashion design to become a stylist. Christian Joy became costume designer to singer Karen O of the rock band the Yeah Yeah Yeahs after meeting her at Antique Boutique in NoHo, where Joy was working. One day, O came in, saw Joy with a handful of outdated prom dresses, and asked her to make her one for a show.

“It was the ugliest dress I ever made,” says Joy.“It was this slashed-up prom dress that said ‘Yeah Yeah Yeahs’ all over it and had fake flowers hanging from it.”

Joy, who is untrained, defends her punk ethos in creating outfits. “You can just do it,” she told O’Connell.“It was the energy that came out of the costume more than the construction of the costume.”

Like most stylists, Joy is content to stay in the background. When she saw one of her designs onstage for the first time, she thought back to her childhood in Iowa. “Even growing up, I knew I was going to do something so cool at some point,” she says. “This is that cool thing that was going to happen to me.”